1. Field of the Invention
The present invention relates generally to medical apparatus and, more particularly, to methods and apparatus for cutting and removing tissue and other materials.
2. Description of Related Art
Turning to FIG. 1, a prior art optical cutter includes a fiber guide tube 5, a water line 7, an air line 9, and an air knife line 11 for supplying pressurized air. A cap 15 fits onto the hand-held apparatus 13 and is secured via threads 17. The fiber guide tube 5 abuts within a cylindrical metal piece 19. Another cylindrical metal piece 21 is a part of the cap 15. The pressurized air from the air knife line 11 surrounds and cools the laser as the laser bridges the gap between the two metal cylindrical objects 19 and 21. Air from the air knife line 11 flows out of the two exhausts 25 and 27 after cooling the interface between elements 19 and 21.
The Nd:YAG laser energy exits from the fiber guide tube 23 and is applied to a target surface of the patient. Water from the water line 7 and pressurized air from the air line 9 are forced into the mixing chamber 29. The air and water mixture is very turbulent in the mixing chamber 29, and exits this chamber through a mesh screen with small holes 31. The air and water mixture travels along the outside of the fiber guide tube 23, and then leaves the tube and contacts the area of surgery.
Other prior art devices include optical cutting systems utilizing the expansion of water to destroy and remove tooth material, such as disclosed in U.S. Pat. No. 5,199,870 to Steiner et al. This prior art approach requires a film of liquid having a thickness of between 10 and 200 xcexcm. U.S. Pat. No. 5,267,856 to Wolbarsht et al. discloses a cutting apparatus that requires water to be inserted into pores of a material and then irradiated with laser energy. In both patents the precision and accuracy of the cut is highly dependent upon the precision and accuracy of the water film on the material or the water within the pores.
The present invention discloses an electromagnetically induced mechanical cutting mechanism, which can provide accurate cutting operations on hard and soft tissues, and other materials as well. Soft tissues may include fat, skin, mucosa, gingiva, muscle, heart, liver, kidney, brain, eye, and vessels, and hard tissue may include tooth enamel, tooth dentin, tooth cementum, tooth decay, amalgam, composites materials, tarter and calculus, bone and cartilage.
The electromagnetically induced cutter is capable of providing extremely fine and smooth incisions, irrespective of the cutting surface. Additionally, a user programmable combination of atomized particles or of a composition of moist air allows for user control of various cutting parameters. The various cutting parameters may also be controlled by changing spray nozzles and electromagnetic energy source parameters. The present invention further does not require any films of water or any particularly porous surfaces to obtain very accurate and controlled cutting. Since thermal heating is not used as the cutting mechanism in one embodiment, thermal damage can be attenuated or eliminated. Adjacent tissue can be spared from substantial thermal damage.
The electromagnetically induced mechanical cutter of the present invention includes an electromagnetic energy source, which focuses electromagnetic energy into a volume of air adjacent to a target surface. The target surface may comprise skin, for example. A user input device can specify a type of cut to be performed, and an atomizer (or moist air generating device) responsive to the user input device places moist air and/or a combination of atomized fluid particles into the volume of air. The electromagnetic energy is focused into the volume of air, and the wavelength of the electromagnetic energy is selected to be substantially absorbed by moisture in the air and/or the atomized fluid particles in the volume of air. Upon absorption of the electromagnetic energy the moisture and/or atomized fluid particles impart mechanical cutting forces onto the target surface.